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PubMed2026

A novel peptide encoded by circTLL1 drives osimertinib resistance in lung cancer by modulating the NT5C2/Ras/PI3K axis.

BACKGROUND: Acquired resistance to osimertinib, a third-generation EGFR tyrosine kinase inhibitor, remains a major clinical challenge in the treatment of non-small cell lung cancer (NSCLC). Although circular RNAs (circRNAs) have been increasingly implicated in drug resistance, most studies have focused on their canonical role as microRNA sponges, while their capacity to encode functional micropeptides remains largely unexplored. This study aimed to identify novel circRNAs involved in osimertinib resistance and to characterize their regulatory functions at the protein level. METHODS: Osimertinib-resistant (OR) NSCLC cell lines were established and validated. High-throughput RNA sequencing was performed to compare the circRNA expression profiles between parental and OR cells. The function of the candidate circRNA was assessed through a series of in vitro and in vivo experiments, including cell viability assays, apoptosis analysis, and xenograft mouse models. Mechanistic investigations involved mass spectrometry, co-immunoprecipitation and western blotting to explore its protein-coding potential and downstream signaling pathways. RESULTS: We identified a novel circRNA, termed circTLL1, that was stably and significantly upregulated in OR-NSCLC cells. Functionally, overexpression of circTLL1 promoted osimertinib resistance, whereas its knockdown restored drug sensitivity both in vitro and in vivo. Mechanistically, we discovered that circTLL1 harbors an open reading frame (ORF) that is translated into a novel 90-amino-acid protein, which we designated circTLL1-90aa. Further investigation revealed that circTLL1-90aa directly interacts with and promotes the degradation of 5'-nucleotidase, cytosolic II (NT5C2), thereby uncoupling nucleotide metabolism from its normal regulatory constraints. The consequent downregulation of NT5C2 leads to elevated GTP levels and leading to the sustained activation of the downstream Ras/PI3K/AKT signaling pathway. CONCLUSION: Our findings unveil a previously unrecognized circRNA/micropeptide/metabolism cascade underlying osimertinib resistance. The identification of the circTLL1-90aa/NT5C2/Ras/PI3K axis not only expands the functional repertoire of the non-coding genome but also provides new insights into the complexity of drug resistance. Given its selective upregulation in resistant cells, circTLL1-90aa holds promise both as a predictive biomarker for treatment stratification and as an actionable therapeutic target, offering a novel strategy to overcome osimertinib resistance in NSCLC patients.

Pyrimidines↗

PubMed1998

A phage display approach for rapid antibody humanization: designed combinatorial V gene libraries.

The development of a new strategy for antibody humanization is described. This strategy incorporates key recognition sequences from the parental rodent antibody into a phage display-based selection strategy. The original sequences of the third complementarity-determining regions (CDRs) of heavy and light chains, HCDR3 and LCDR3, were maintained and all other sequences were replaced by human sequences selected from phage-displayed antibody libraries. This approach was applied to the humanization of mouse mAb LM609 that is directed to human integrin alphav beta3 and has potential applicability in cancer therapy as an antiangiogenic agent. We demonstrate this approach (i) provides a rapid route for antibody humanization constraining the content of original mouse sequences in the final antibodies to the most hypervariable of the CDRs; (ii) generates several humanized versions with different sequences at the same time; (iii) results in affinities as high as or higher than the affinity of the original antibody; and (iv) retains the antigen and epitope specificity of the original antibody. The production of multiple humanized variants may present advantages in the selection of antibodies that are more readily expressed on a large scale and could be important in therapeutic regimens that call for long-term treatment with antibodies in which antiidiotypic responses might be avoided by administration of alternative antibodies.

Amino Acid Sequence↗

PubMed1987

Suppressible base substitution mutations induced by angelicin (isopsoralen) in the Escherichia coli lacI gene: implications for the mechanism of SOS mutagenesis.

Angelicin- plus near-UV-induced mutations were umuC dependent in Escherichia coli K-12. Angelicin, a monofunctional psoralen derivative, is believed to damage DNA almost exclusively at pyrimidine bases. To broaden our knowledge about the mutagenic specificity of SOS-dependent mutagens, we determined the mutational specificity of 233 suppressible lacI mutations induced by angelicin. More than 90% of the nonsense mutations arose via transversion substitutions. The three most frequently mutated sites were at A-T base pairs and accounted for more than one-third of all induced nonsense mutations. The two hottest sites were at the only occurrences of the 5'-TATA-3' tetranucleotide in lacI, a sequence expected to be a preferred binding site for a psoralen. Both A-T-to-T-A and A-T-to-C-G transversions were well induced by angelicin treatment, but the frequency of each transversion depended on the particular site. We also detected significant induction of transversion mutations at G-C sites. The induction of transversions by an SOS-dependent mutagen that generates lesions at pyrimidines supports the idea that DNA lesions influence the selection of bases that are incorporated via the process of SOS repair.

Base Sequence↗

PubMed1999

Molecular and functional analysis of mouse decay accelerating factor (CD55).

Molecular cloning of mouse decay accelerating factor (DAF; CD55) predicted two forms of the molecule, one transmembrane (TM) and the other glycosylphosphatidylinositol (GPI)-anchored; these are encoded by separate genes termed Daf-GPI and Daf-TM. In the present study several additional isoforms of mouse DAF, generated by alternative splicing from these genes, are described. Northern-blot analysis of RNA and reverse transcriptase-PCR from various tissues indicated that spleen and testis expressed high levels of DAF, which comprised several species. These species were cloned and sequence analysis revealed various novel forms in addition to those previously reported. Two novel forms were derived from the Daf-TM gene but the transmembrane sequence defined previously was replaced by a unique GPI-anchor addition sequence; one clone also had part of the serine/threonine/proline (STP) region deleted. A third clone, encoding a transmembrane protein, was also derived from this gene but the entire STP region was deleted. A fourth clone, derived from the Daf-GPI gene, contained a novel C-terminal sequence, suggestive of a secreted form of the protein. Two DAF cDNAs (TM and GPI-anchored) were stably expressed in Chinese hamster ovary cells. When these cells were attacked with mouse or rat complement and analysed for C3b deposition, DAF-transfected cells had greatly reduced C3b deposition compared with controls. Transfection with DAF also conferred protection from complement in a cell-lysis assay, and a soluble, recombinant form of mouse DAF inhibited complement in a haemolytic assay.

Alternative Splicing↗

PubMed1986

Fine specificity analysis of idiotype-specific suppressor factors that block a delayed-type hypersensitivity response to M315: evidence supporting a role for somatic mutations in the variable region of the lambda 2 chain of M315.

The delayed-type hypersensitivity (DTH) response in BALB/c mice to the idiotype of M315 (alpha,lambda 2), a BALB/c myeloma protein, can be suppressed by a single i.v. injection of soluble M315. This suppression involves the generation of suppressor T cells. Mice tolerized by M315 produce subcellular factors that suppress the M315-DTH response. Such suppressor factors can be obtained by mechanical disruption of spleen cells or thymocytes from mice treated i.v. with M315. The fine specificity of the factor was studied using various immunoadsorbents such as L315 and germline V lambda 2 chain-Sepharose beads with known amino acid sequences. The results indicated that the specificity of the factor depended on three contiguous somatically mutated amino acid residues, Phe94, Arg95 and Asn96, in the third hypervariable region of the V domain of the L chain of M315.

Animals↗

PubMed2003

Antisense technologies. Improvement through novel chemical modifications.

Antisense agents are valuable tools to inhibit the expression of a target gene in a sequence-specific manner, and may be used for functional genomics, target validation and therapeutic purposes. Three types of anti-mRNA strategies can be distinguished. Firstly, the use of single stranded antisense-oligonucleotides; secondly, the triggering of RNA cleavage through catalytically active oligonucleotides referred to as ribozymes; and thirdly, RNA interference induced by small interfering RNA molecules. Despite the seemingly simple idea to reduce translation by oligonucleotides complementary to an mRNA, several problems have to be overcome for successful application. Accessible sites of the target RNA for oligonucleotide binding have to be identified, antisense agents have to be protected against nucleolytic attack, and their cellular uptake and correct intracellular localization have to be achieved. Major disadvantages of commonly used phosphorothioate DNA oligonucleotides are their low affinity towards target RNA molecules and their toxic side-effects. Some of these problems have been solved in 'second generation' nucleotides with alkyl modifications at the 2' position of the ribose. In recent years valuable progress has been achieved through the development of novel chemically modified nucleotides with improved properties such as enhanced serum stability, higher target affinity and low toxicity. In addition, RNA-cleaving ribozymes and deoxyribozymes, and the use of 21-mer double-stranded RNA molecules for RNA interference applications in mammalian cells offer highly efficient strategies to suppress the expression of a specific gene.

Animals↗

PubMed1999

Phylogenetic relationships in the mushroom genus Coprinus and dark-spored allies based on sequence data from the nuclear gene coding for the large ribosomal subunit RNA: divergent domains, outgroups, and monophyly.

Phylogenetic relationships were investigated in the mushroom genus Coprinus based on sequence data from the nuclear encoded large-subunit rDNA gene. Forty-seven species of Coprinus and 19 additional species from the families Coprinaceae, Strophariaceae, Bolbitiaceae, Agaricaceae, Podaxaceae, and Montagneaceae were studied. A total of 1360 sites was sequenced across seven divergent domains and intervening sequences. A total of 302 phylogenetically informative characters was found. Ninety-eight percent of the average divergence between taxa was located within the divergent domains, with domains D2 and D8 being most divergent and domains D7 and D10 the least divergent. An empirical test of phylogenetic signal among divergent domains also showed that domains D2 and D3 had the lowest levels of homoplasy. Two equally most parsimonious trees were resolved using Wagner parsimony. A character-state weighted analysis produced 12 equally most parsimonious trees similar to those generated by Wagner parsimony. Phylogenetic analyses employing topological constraints suggest that none of the major taxonomic systems proposed for subgeneric classification is able to completely reflect phylogenetic relationships in Coprinus. A strict consensus integration of the two Wagner trees demonstrates the problematic nature of choosing outgroups within dark-spored mushrooms. The genus Coprinus is found to be polyphyletic and is separated into three distinct clades. Most Coprinus taxa belong to the first two clades, which together form a larger monophyletic group with Lacrymaria and Psathyrella in basal positions. A third clade contains members of Coprinus section Comati as well as the genus Leucocoprinus, Podaxis pistillaris, Montagnea arenaria, and Agaricus pocillator. This third clade is separated from the other species of Coprinus by members of the families Strophariaceae and Bolbitiaceae and the genus Panaeolus.

Coprinus↗

PubMed1995

Functional organization of tau proteins during neuronal differentiation and development.

Tau proteins play major regulatory roles in the organization and integrity of the cytoskeletal network. In neurons, a specific axonal compartmentalization of tau has been shown. However, recent studies demonstrate that tau displays a widespread distribution in a variety of non-neuronal cell types. These proteins have been found in human fibroblasts and in several transformed cell lines. The heterogeneous family of tau is formed by a set of molecular species that share common peptide sequences. There is a single gene that contains several exons encoding for the six different tau isoforms in mammalian brain. Alternative splicing of a common RNA transcript as well as post-translational modifications contribute to its heterogeneity. Tau isoforms generated by splicing differ from one another by having either three or four repeats in their C-terminal half, and a variable number of inserts in their N-terminal moiety. These repeats have been shown to constitute microtubule-binding motifs. In this review some relevant aspects of tau function and its regulation are analyzed. Three major topics are discussed. The first one focuses on the tau roles in regulating the interactions between microtubules with actin filaments and with intermediate filament systems. Another problem deals with the question of whether tau isoforms segregate into functionally different subsets of microtubules in axonal processes, or tau associates with these polymers in a random fashion. The third question that emerges is the involvement of tau and tau-like proteins in morphogenetic events. The regulation of the interactions of DMAP-85, a recently discovered tau-like protein, with the cytoskeleton during development of Drosophila melanogaster is analyzed.

Amino Acid Sequence↗

PubMed2001

Folate-binding triggers the activation of folylpolyglutamate synthetase.

Folic acid is an essential vitamin for normal cell growth, primarily through its central role in one-carbon metabolism. Folate analogs (antifolates) are targeted at the same reactions and are widely used as therapeutic drugs for cancer and bacterial infections. Effective retention of folates in cells and the efficacy of antifolate drugs both depend upon the addition of a polyglutamate tail to the folate or antifolate molecule by the enzyme folylpolyglutamate synthetase (FPGS). The reaction mechanism involves the ATP-dependent activation of the free carboxylate group on the folate molecule to give an acyl phosphate intermediate, followed by attack by the incoming L-glutamate substrate. FPGS shares a number of structural and mechanistic details with the bacterial cell wall ligases MurD, MurE and MurF, and these enzymes, along with FPGS, form a subfamily of the ADP-forming amide bond ligase family. High-resolution crystallographic analyses of binary and ternary complexes of Lactobacillus casei FPGS reveal that binding of the first substrate (ATP) is not sufficient to generate an active enzyme. However, binding of folate as the second substrate triggers a large conformational change that activates FPGS and allows the enzyme to adopt a form that is then able to bind the third substrate, L-glutamate, and effect the addition of a polyglutamate tail to the folate.

Adenosine Triphosphate↗

PubMed2005

Deoxyuridine is generated preferentially in the nontranscribed strand of DNA from cells expressing activation-induced cytidine deaminase.

Activation-induced cytidine deaminase (AID) is required for somatic hypermutation and class switch recombination of Ig genes in B cells. Although AID has been shown to deaminate deoxycytidine to deoxyuridine in DNA in vitro, there is no physical evidence for increased uracils in DNA from cells expressing AID in vivo. We used several techniques to detect uracil bases in a gene that was actively transcribed in Escherichia coli cells expressing AID. Plasmid DNA containing the gene was digested with uracil-DNA glycosylase to remove uracil, and apurinic/apryimidinic endonuclease to nick the abasic site. The nicked DNA was first analyzed using alkaline gel electrophoresis, in which there was a 2-fold increase in the linear form of the plasmid after AID induction compared with plasmid from noninduced bacteria. Second, using a quantitative denaturing Southern blot technique, the gene was predominantly nicked in the nontranscribed strand compared with the transcribed strand. Third, using ligation-mediated PCR, the nicks were mapped on the nontranscribed strand and were located primarily at cytosine bases. These data present direct evidence for the presence of uracils in DNA from cells that are induced to express AID, and they are preferentially generated at cytosines in the nontranscribed strand during transcription.

Base Sequence↗

PubMed2006

Brugia malayi: effects of radiation and culture on gene expression in infective larvae.

Third-stage infective larvae (L3i) of Brugia malayi are developmentally arrested in mosquitoes but must quickly adapt to a new environment when they enter mammalian hosts to initiate infections. These changes can be studied by in vitro culture of L3 (L3c) under conditions that permit molting of L3-L4. Irradiated L3 (L3ir) have stunted growth and limited lifespan in mammalian hosts, and they induce high levels of immunity to challenge infections in animal models. This study explored differences in gene expression in L3i, L3c and L3ir by expressed sequence tag EST generation and qRT-PCR. 2506 ESTs generated from cDNA libraries constructed from L3i, L3c and L3ir were grouped into 1309 gene clusters. Despite extensive prior sampling from B. malayi (>22,000 ESTs in dbEST), 73% of the L3 clusters described here are novel. Sixty-three percentage of the clusters have homology to proteins from other species including 187 specific to nematodes and 141 that have to date only been described in non-nematode species. The transcript levels of 62 candidates for up- or down-regulation in L3i, L3c and L3ir based on EST frequencies were evaluated by qRT-PCR. Twenty-eight were confirmed to have > or = 3-fold differences in expression. Genes coding for proteins believed to be involved in establishment of infection, host adaptation and targets of protective immunity were confirmed to have higher expression in L3i than in L3c. Some of the genes that were down-regulated in L3c were highly expressed in L3ir. This study provides an improved description of the adaptations that accompany the transition from L3i to L3c and the special ability of L3ir to induce protective immunity.

Aedes↗

PubMed2006

Carbosilane dendrimeric carbodiimides: site isolation as a lactamization tool.

The convergent syntheses of three generations of carbosilane dendrimeric carbodiimides are described. The wedge-type building blocks were synthesized in a divergent way, starting from allyl chloride and a repetitive sequence of hydrosilylation with HSiCl3 and a Grignard reaction with allylmagnesium bromide. Hydrogenation of the terminal double bonds led to inert and stable wedges. The chloride substituent at the focal point was transformed into several functional groups that eventually led to dendrimeric structures with a carbodiimide core. The extent of the site isolation effect of the dendrimers was studied with dilution experiments monitored by FT-IR spectroscopy on the corresponding dendrimeric ureas. These studies showed that only the first generation self-aggregates via hydrogen bonding, while the second and the third do not, implying isolation of core-bound moieties. The dendrimeric carbodiimides mediated lactamization reactions to obtain homodiketopiperazines.

Journal Article↗

PubMed1998

The transferrin binding protein B of Moraxella catarrhalis elicits bactericidal antibodies and is a potential vaccine antigen.

The transferrin binding protein genes (tbpA and tbpB) from two strains of Moraxella catarrhalis have been cloned and sequenced. The genomic organization of the M. catarrhalis transferrin binding protein genes is unique among known bacteria in that tbpA precedes tbpB and there is a third gene located between them. The deduced sequences of the M. catarrhalis TbpA proteins from two strains were 98% identical, while those of the TbpB proteins from the same strains were 63% identical and 70% similar. The third gene, tentatively called orf3, encodes a protein of approximately 58 kDa that is 98% identical between the two strains. The tbpB genes from four additional strains of M. catarrhalis were cloned and sequenced, and two potential families of TbpB proteins were identified based on sequence similarities. Recombinant TbpA (rTbpA), rTbpB, and rORF3 proteins were expressed in Escherichia coli and purified. rTbpB was shown to retain its ability to bind human transferrin after transfer to a membrane, but neither rTbpA nor rORF3 did. Monospecific anti-rTbpA and anti-rTbpB antibodies were generated and used for immunoblot analysis, which demonstrated that epitopes of M. catarrhalis TbpA and TbpB were antigenically conserved and that there was constitutive expression of the tbp genes. In the absence of an appropriate animal model, anti-rTbpA and anti-rTbpB antibodies were tested for their bactericidal activities. The anti-rTbpA antiserum was not bactericidal, but anti-rTbpB antisera were found to kill heterologous strains within the same family. Thus, if bactericidal ability is clinically relevant, a vaccine comprising multiple rTbpB antigens may protect against M. catarrhalis disease.

Amino Acid Sequence↗

PubMed2001

Use of transposon Tn5367 mutagenesis and a nitroimidazopyran-based selection system to demonstrate a requirement for fbiA and fbiB in coenzyme F(420) biosynthesis by Mycobacterium bovis BCG.

Three transposon Tn5367 mutagenesis vectors (phAE94, pPR28, and pPR29) were used to create a collection of insertion mutants of Mycobacterium bovis strain BCG. A strategy to select for transposon-generated mutants that cannot make coenzyme F(420) was developed using the nitroimidazopyran-based antituberculosis drug PA-824. One-third of 134 PA-824-resistant mutants were defective in F(420) accumulation. Two mutants that could not make F(420)-5,6 but which made the biosynthesis intermediate FO were examined more closely. These mutants contained transposons inserted in two adjacent homologues of Mycobacterium tuberculosis genes, which we have named fbiA and fbiB for F(420) biosynthesis. Homologues of fbiA were found in all seven microorganisms that have been fully sequenced and annotated and that are known to make F(420). fbiB homologues were found in all but one such organism. Complementation of the fbiA mutant with fbiAB and complementation of the fbiB mutant with fbiB both restored the F(420)-5,6 phenotype. Complementation of the fbiA mutant with fbiA or fbiB alone did not restore the F(420)-5,6 phenotype, but the fbiA mutant complemented with fbiA produced F(420)-2,3,4 at levels similar to F(420)-5,6 made by the wild-type strain, but produced much less F(420)-5. These data demonstrate that both genes are essential for normal F(420)-5,6 production and suggest that the fbiA mutation has a partial polar effect on fbiB. Reverse transcription-PCR data demonstrated that fbiA and fbiB constitute an operon. However, very low levels of fbiB mRNA are produced by the fbiA mutant, suggesting that a low-level alternative start site is located upstream of fbiB. The specific reactions catalyzed by FbiA and FbiB are unknown, but both function between FO and F(420)-5,6, since FO is made by both mutants.

Antitubercular Agents↗

PubMed1990

Structural model for T-cell recognition of HLA class II-associated alloepitopes.

In an effort to investigate the structure-function relationship of HLA class II molecules vis-à-vis alloepitope expression, cloned T-cell reagents were used to define polymorphic epitopes associated with DR and DQ molecules. DNA sequences of genes encoding allelic or isotypic DR or DQ molecules that appear to express the same T-cell-defined epitopes were compared in an attempt to identify association of shared sequences with shared epitopes. When sequence sharing is associated with shared epitope expression, we suggest that it is the shared sequence that encodes the epitope in question. Based on the hypothetical three-dimensional structure of the class II molecule, an approximation is made as to which parts of the HLA class II molecule are involved in alloepitope expression. T-cell clones were generated from cells primed against HLA-DR2 haplotypes representing the cellularly defined subgroups Dw2 or Dw21 (previously designated MN2, FJ0, or Tb24). Those clones determined to be DR- or DQ-directed based on monoclonal antibody inhibition assays were tested by panel cell analysis utilizing DR2-positive and DR2-negative target cells. The data support the concept that amino acids 67, 70, 71, and 74 for DR molecules and amino acids 57, 70, and 71 for DQ molecules, which appear to comprise one face of the alpha helix, are of primary importance in T-cell recognition. In other cases, sharing of both the second hypervariable region (amino acids 25-33) and the third hypervariable region (amino acids 67-74) appears necessary to explain epitope sharing for DR molecules. We emphasize that the involvement of these two hypervariable regions may indicate that alloepitope expression involves the complex of class II molecule plus peptide, with the second HVR primarily involved in determining which peptides are bound and the third in T-cell receptor (TcR) recognition and/or peptide binding; we do not rule out that conformational changes of the second HVR can induce conformational changes in the third HVR. Finally, shared alloepitopes detected by some clones could not be explained based on shared primary sequences.

Amino Acid Sequence↗

PubMed2000

Did nucleotides or amino acids drive evolutionary conservation of the WT1 +/-KTS alternative splice?

Evolutionary comparisons frequently pinpoint crucial parts of a protein but, even within coding regions, nucleotides can do more than determine amino acid sequence. One highly conserved feature of the Wilms' tumour suppressor gene, WT1, is the potential, following alternative pre-mRNA splicing, to insert three amino acids (KTS) between the third and fourth zinc fingers. The nucleotides at this position simultaneously define amino acids and the alternative splice site. At the protein level this insertion influences DNA binding affinity and specificity, protein-protein interactions and subnuclear localization. Mutations within the +/-KTS splice junction lead to severe urogenital developmental abnormalities such as Frasier syndrome, indicating that the isoform ratio is critical for wild-type function. Using a series of site-directed mutations in both the genomic and cDNA context, the nucleotide-amino acid relationship was investigated. Mutational analysis within the cDNA suggests that the precise amino acids inserted may not be critical, but rather the disruption of the zinc finger structure alone may be sufficient to generate proteins with different in vitro properties. However, analysis within the genomic context suggests that the precise structure of the splice junction is crucial in retaining the balance between the isoforms, and this may account for the high nucleo-tide conservation of this unusual gene structure from fish to mammals.

Alternative Splicing↗

PubMed2004

Radiation and third-generation chemotherapy.

All of the third-generation chemotherapeutic agents reviewed in this article are independently active against NSCLC, although the agents differ significantly in their cellular and molecular mechanisms of cytotoxicity. All have also been shown to potentiate radiation effects, and thus are promising in exerting further cytotoxicity when used in combination chemoradiation therapy for locally advanced NSCLC. Although the toxicity to normal tissue varies among these agents when used alone, phase I/II clinical results consistently demonstrated higher risk and severity of esophagitis and pneumonitis when these agents were administered concurrently with thoracic radiation. These results were consistent with the radiosensitization properties of all these agents. Nonetheless, most chemoradiation combinations have been made feasible through careful phase I studies that establish safe doses of these agents given concurrently with radiation. Indeed, phase I outcomes consistently have demonstrated the need for dose reduction compared with doses applied in the stage IV, metastatic disease setting (see Tables 1 and 2). There have been many different dose schedules in phase I/II studies for stage III NSCLC, and most have yielded improved response rates with these agents. For all these agents discussed, multiagent chemoradiation increased toxicity when compared with single agent chemoradiation, particularly in the risk of neutropenia, and the tumor response rates were no better than single-agent chemoradiation. Most studies have not reached an adequate interval for survival endpoint to assess the impact on survival using multiagent chemoradiation. A few earlier studies using paclitaxel chemoradiation, in fact, showed that the significant improvement in tumor response rate resulted in only a small gain in survival outcome. Despite much preclinical research conducted with these agents, the optimal sequence and dose of drug and the optimal schedule for combining the two modalities remain unknown. Optimal sequencing of the chemoradiation regimens may improve distant disease control and primary tumor control, as was seen in studies that administered both full-dose induction chemotherapy and concurrent chemoradiation at reduced drug dose and in studies that administered consolidative, full-dose chemotherapy after chemoradiation. Strategically altering the treatment schedule may also enhance the radiosensitizing effects while keeping toxicity low, such as was seen in the pulsed low-dose paclitaxel chemoradiation reported by Chen et al . This pulsed low-dose schedule resulted in superior tumor response (100%) and durable primary tumor control while keeping the toxicity low. Other methods to minimize normal tissue injury and to deliver higher radiation doses, such as conformal three-dimensional radiotherapy that excludes nontarget tissues from the radiation field, are under investigation. Marks and colleagues were able to deliver radiation to 80 Gy using accelerated hyperfractionation radiation after induction chemotherapy. Intensity-modulated radiotherapy is expected to revolutionize the targeting of tumor and exclusion of normal tissues from the high-dose radiation volume in the future. Integrating biologic response modifiers, radioprotectors, and molecular targeting strategies also are being investigated. It remains unclear which agent among the third-generation drugs performs better for combination chemoradiation. The CALGB 9431 study reported by Vokes et al provided some preliminary information, in that it was a randomized phase II study of a three-arm comparison of cisplatin-containing, two-drug combination chemoradiation with one of the third-generation agents. Although direct statistical comparison between the treatment arms was not valid for a phase II setting, such an analysis did indeed reveal similar overall response rates for these three arms. Chemoradiation using third-generation chemotherapeutic agents has improved local tumor response rates, with enhanced radiation toxicity such as esophagitis and pneumonitis. The challenge of targeting distant disease control for locally advanced NSCLC continues.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Genome-wide analysis of gene expression in adult Anopheles gambiae.

With their genome sequenced, Anopheles gambiae mosquitoes now serve as a powerful tool for basic research in comparative, evolutionary and developmental biology. The knowledge generated by these studies is expected to reveal molecular targets for novel vector control and pathogen transmission blocking strategies. Comparisons of gene-expression profiles between adult male and nonblood-fed female Anopheles gambiae mosquitoes revealed that roughly 22% of the genes showed sex-dependent regulation. Blood-fed females switch the majority of their metabolism to blood digestion and egg formation within 3 h after the meal is ingested, in detriment to other activities such as flight and response to environment stimuli. Changes in gene expression are most evident during the first, second and third days after a blood meal, when as many as 50% of all genes showed significant variation in transcript accumulation. After laying the first cluster of eggs (between 72 and 96 h after the blood meal), mosquitoes return to a nongonotrophic stage, similar but not identical to that of 3-day-old nonblood-fed females. Ageing and/or the nutritional state of mosquitoes at 15 days after a blood meal is reflected by the down-regulation of approximately 5% of all genes. A full description of the large number of genes regulated at each analysed time point and each biochemical pathway or biological processes in which they are involved is not possible within the scope of this contribution. Therefore, we present descriptions of groups of genes displaying major differences in transcript accumulation during the adult mosquito life. However, a publicly available searchable database (http://www.angagepuci.bio.uci.edu/) has been made available so that detailed analyses of specific groups of genes based on their descriptions, functions or levels of gene expression variation can be performed by interested investigators according to their needs.

Aging↗